Abstract : The major purpose of this investigation was to provide experimental data for use in developing empirical switching models for practical applications. The properties of flux switching from various partially set states of a ferrite thinring core were investigated. The partially set states were obtained by first thoroughly clearing the core to negative remanence, and then partially setting with a rectangular pulse whose ampli tude, and duration were adjusted to partially set the desired amount of flux. It was found that the partial setting very significantly affected the subsequent switching in a manner not anticipated on the basis of domain wall switching. This was true not only for very large applied H fields, but also for H ranging all the way down to the coercive field. Thus, even though rotational switching may explain some of the effects at high fields, it offers no explanation at very low fields where rotational switching is presumed not to occur. It was found that this model could be modified to approximately describe switching from the partially set states by introducing a new parameter phi sub c. In general the values of phi sub c, the dynamic threshold F sub zero, and the linear coefficient of the model, k, were all found to be changed by partial setting. (Author)